Fix a typo (cannot initialize a reference to NULL).
Fix a typo (cannot initialize a reference to NULL).

Change-Id: Id8b4e9400b157492b9b402792dc4133b6613a461

candy7393/VTK,mspark93/VTK,demarle/VTK,berendkleinhaneveld/VTK,gram526/VTK,candy7393/VTK,johnkit/vtk-dev,jmerkow/VTK,hendradarwin/VTK,candy7393/VTK,johnkit/vtk-dev,johnkit/vtk-dev,candy7393/VTK,sumedhasingla/VTK,msmolens/VTK,demarle/VTK,keithroe/vtkoptix,jmerkow/VTK,sumedhasingla/VTK,msmolens/VTK,aashish24/VTK-old,candy7393/VTK,mspark93/VTK,berendkleinhaneveld/VTK,sumedhasingla/VTK,aashish24/VTK-old,demarle/VTK,collects/VTK,mspark93/VTK,johnkit/vtk-dev,biddisco/VTK,mspark93/VTK,demarle/VTK,candy7393/VTK,sankhesh/VTK,aashish24/VTK-old,candy7393/VTK,berendkleinhaneveld/VTK,ashray/VTK-EVM,johnkit/vtk-dev,jmerkow/VTK,collects/VTK,jmerkow/VTK,hendradarwin/VTK,msmolens/VTK,johnkit/vtk-dev,candy7393/VTK,demarle/VTK,SimVascular/VTK,mspark93/VTK,sankhesh/VTK,keithroe/vtkoptix,ashray/VTK-EVM,ashray/VTK-EVM,demarle/VTK,demarle/VTK,mspark93/VTK,sankhesh/VTK,gram526/VTK,keithroe/vtkoptix,sumedhasingla/VTK,aashish24/VTK-old,SimVascular/VTK,berendkleinhaneveld/VTK,SimVascular/VTK,keithroe/vtkoptix,aashish24/VTK-old,johnkit/vtk-dev,ashray/VTK-EVM,gram526/VTK,sumedhasingla/VTK,msmolens/VTK,hendradarwin/VTK,ashray/VTK-EVM,mspark93/VTK,mspark93/VTK,biddisco/VTK,keithroe/vtkoptix,gram526/VTK,sankhesh/VTK,SimVascular/VTK,ashray/VTK-EVM,jmerkow/VTK,hendradarwin/VTK,msmolens/VTK,biddisco/VTK,jmerkow/VTK,jmerkow/VTK,jmerkow/VTK,biddisco/VTK,biddisco/VTK,sankhesh/VTK,collects/VTK,hendradarwin/VTK,keithroe/vtkoptix,msmolens/VTK,gram526/VTK,collects/VTK,msmolens/VTK,SimVascular/VTK,sankhesh/VTK,gram526/VTK,gram526/VTK,berendkleinhaneveld/VTK,gram526/VTK,SimVascular/VTK,aashish24/VTK-old,hendradarwin/VTK,ashray/VTK-EVM,collects/VTK,berendkleinhaneveld/VTK,sumedhasingla/VTK,SimVascular/VTK,biddisco/VTK,keithroe/vtkoptix,sumedhasingla/VTK,hendradarwin/VTK,ashray/VTK-EVM,berendkleinhaneveld/VTK,sankhesh/VTK,SimVascular/VTK,sumedhasingla/VTK,msmolens/VTK,demarle/VTK,keithroe/vtkoptix,sankhesh/VTK,biddisco/VTK,collects/VTK